In optical communication systems, such as those which transmit data over optical fiber cable links, the opto-electronic transducer to which the light transmitted by an optical fiber is coupled may take the form of an avalanche photodiode. The photodiode is normally biased to operate over a prescribed range wherein it converts optical input signals transmitted over the fibers into an electrical current output proportional to the optical signals. An important criterion in achieving accurate photo-current conversion is the operational characteristics of the photodiode. As these characteristics are affected by both environmental variations, such as temperature fluctuations, and electrical circuit variations, such as power supply voltage drifts, some means must be provided to provide the necessary compensation in an effort to obtain reliable operation of the photodiode. Among various configurations that have been proposed to deal with variations in optical system parameters are those described in the United States Patents to Chilton U.S. Pat. No. 3,626,188, Rose U.S. Pat. No. 3,657,543, Maione et al. U.S. Pat. No. 4,019,048, Coleby U.S. Pat. No. 3,793,522, Dahlinger U.S. Pat. No. 4,001,614, and Andersson et al. U.S. Pat. No. 4,015,188. Similarly, the United States . Patent to Burrous et al. U.S. Pat. No. 3,705,316 describes circuitry for providing temperature compensation for a light source employing a light emitting diode. Unfortunately, the various implementations described in the above literature are, for the most part, complex and do not practically provide the complete gain control and overall compensation that is necessary in an avalanche photodiode receiver.